This can be done in different ways
Right click on a terminal.
Choose Select name.
This opens the dialog Select Name.
Click the icon DATA in the upper toolbar.
This opens the dialog Component Data.
Type a name for the terminal followed by a : and the first connection for this (part of the) terminal (block), ie –X1:1.
Activate automatic numbering by clicking Ctrl and + simultaneously. Click ok.
Renumbering can also be done with the Tool / Rename symbols.